Ok, so my questions are:

-What do you consider to be a safe boost level for E85 for roadracing in say 80-100F track temps on a BUILT 2.0L Stock Frame Turbo (CBRD BBK-Full)? Is 26-27psi about right? Running all session long.

-What do you consider to be an aggressive boost level for E85 for roadracing in say 80-100F on a BUILT 2.0L Stock Frame Turbo (CBRD BBK-Full)? Is 29psi about right for 1 or 2 hot laps per session.


Please answer if you have first hand road race experience and not friend of a friends brother story.

Mods in signature. Same with power/torque etc..

Thanks!

 

I've run a stock 2.0 on stock turbo at ~27 psi for 25 minute sessions before. I'd say with a built 2.0 you'll be fine at that level.

I think you'll be fine at 29 psi (maybe higher) for a lap or two. Log the first session that you try to see how the engine likes it, then go from there.

 

^Agreed! I've run numerous 25min session boosting 27psi on my stock block stock turbo 2.0L and no issues and EGT temps stay within range with no issues...I run a 3.5" ETS Intercooler...Even running 8/10ths laps I don't encounter any issues...As long as your tune isn't right on the edge then you should be fine with 28-30psi on E85...Keep an eye on your EGT's...

 

Hoping there may be more feedback about this topic now that more people are running on corn. I also have a twist to the original question.

My car is stock block (stock cams) with MAP EF2 turbo conservatively tuned on the street. I'm basically running my 3port at 100% across the board and that results in the following:


I'm hit 30psi from 3800-5200 before it starts to drop off. Keep in mind the car doesn't really drop below 5200 all that often when on a road course. Anyway this is what I ran on track all last year without issue but I can't say I wasn't worried. I'm not a professional tuner and 30psi just feels unnatural LOL.

This year I've been thinking about getting dyno tuned. I'm not necessarily looking for the most power but rather something potent yet safe for HPDE events. That leads the the question what is a "proper" boost setting for corn fueled open track lapping cars?

I know there is at least 3-4* of timing left in the current tune which could be another 40whp. If that is the case should I set boost to peak at 25* and add in the timing or since I don't seem to be heat soaking should I leave the boost alone and better dial in timing to a known safe value? Obviously I'm not "racing" so I don't need to run a bleeding edge tune but I don't want to leave safe power on the table either.

Please share your thoughts and experience.

(EDIT: I have fattened up the AF ration above 6k but I still keep it around 12:1)

 

Stock motor/turbo, running e85 with 27psi falling to 21psi at redline. 398whp. No problems yet...

Just make sure you are feeding your motor real e85. Pickup a cheap ethanol test bottle.

 

I ran 28 psi (peak) on a stock block Evo IX for 9 events without any issues. Now I got cams and headstuds, and am running about 24 PSI however.

 

I have run 29-30 on a stock Evo 9 turbo and stock IC for 20 min sessions in 85-90 degree heat here in AZ. No issues.

 

30 psi here in TX, 20-25 min session for years until the stock motor let go.

 

Well it sounds like 30psi really isn't unreasonable which is really good to hear. Thanks for the feedback fellas!

 

I was running on 26 psi with 93 for 2 years for 20-25 min sessions with a BBK-Full with no real problems. I have an E85 tune now and a BBK-3B running 31 psi, but only for TT not HPDE. None of my tracks sell E85 and I couldn't possibly bring enough fuel for 20-25 min sessions at 500+ whp.

 

Anyone have experience with 25 min of track time and a big turbo? Like a HTA3586 on E85?

 

I run 28-29psi on E85 with my 2.3L GT3076R. It's done this for years now.

 

I guess I don't really understand the question. If your tune is safe, your tune is safe. I think what you are getting at is in the case your water cooling system, intake charge air cooling system or oil cooling system is insufficient, how much should you detune the car for safe function at extremely elevated temps. Is that your question?

If your oil temps and water temps and air temps are not kept in check, the engine will be more knock-prone and you'll need to detune it from kill. But if you keep those in check I say run as much as you can until the turbo starts loosing efficiency and you get diminishing returns.

 

You are right that was a bit vague and it's hard to communicate my concerns ..... I guess 30psi seems extreme to me mainly because I must be working the turbo quite hard and I'm probably introducing loads of heat. That being said at 100mph you can easily cool the FMIC while keeping H2O temps in check and E85 pretty much zaps the remaining heat out of the intake charge so how risky is it?

In the before time I ran 26psi on 110 leaded at 12:1 AFR without concern I'm just curious if 30psi on E85 at 12:1 AFR is easier on motor I guess. Probably hard compute but I'd like to determine what the sweet spot is where I'm not creating unnecessary heat yet not leaving gobs of power on the table.

I'm also wondering how detuned your E85 maps are for lapping. Did you go dyno on 30psi max out the HP and pull back a couple * of timing, do you lower boost for track days or do you go out there with the tune on kill? My car makes its best power at 30psi and in its current state of tune I can still see 10HP jumps from 1* of timing but without a dyno tune I'm afraid I may push it too far.

I'm ashamed to admit this but I don't monitor oil temps, coolant temps or air intake temps. I simply use good parts and fluids and cross my fingers that everything plays nice together.

 

Well I think you are asking for trouble if you dont monitor the vital signs, Why?